Usage
ADD for iPhoto works just like the original (A)perture (D)uplicate (D)etector. When the run is complete, yoour potential duplicate images will be tagged with one or more keywords. Here are the meanings of the keywords:
One more thing, iPhoto only supports a flat keyword hierarchy, unlike Aperture.
Scan Library
Scan Library does a full and comprehensive scan of all images in your library and performs ImageIQ on potential duplicates.
Each image is compared to every other image. There's a lot going on, so if you have a large number of images in your library you'll have to be patient.
It is irrelevant what sort order the images are presented to ADD. Once complete, you'll have a full set of date, filename, and hash duplicates ready for you to process for deletion.
Scan Selection
Scan Selection does a full and comprehensive scan of only the images you have selected within iPhoto and performs ImageIQ on potential duplicates.
It is irrelevant what sort order the images are presented to ADD. Once complete, you'll have a full set of date, filename, and hash duplicates ready for you to process for deletion.
After The Scan
There is also a tutorial on what to do once ADD for iPhoto has finished its job.